Even though North Korea’s recent test of a medium-range ballistic missile failed, the event still raised concerns among their neighbors to the south. To counter the threat, and potential aggression by China as well, South Korea is placing considerable faith in THAAD – the Terminal High Altitude Area Defense system.

Wired Magazine reports that the U.S. deployed THAAD to South Korea in March, with plans to have it up and running sometime this summer.
Under development since the early 1990s, THAAD is touted as a nearly fail-safe system for countering missile attacks. Lockheed-Martin, its manufacturer, said THAAD has had “100 percent mission success” since 2005.

“The THAAD system provides the critical capability to defend against short and medium ranged ballistic missiles,” Lockheed Martin said on its Web site.
THAAD uses a radar to detect incoming threats. Its fire-control and communications support equipment then identify and engage the target, and fire an interceptor from a truck-mounted launcher. The enemy missile is destroyed when the THAAD round collides with it.

The deployment of THAAD to South Korea has caught the attention of China, which has expressed concerns that the system could threaten its national security. Wired reports that Chinese concerns are hard to pinpoint. The system would not be capable of hitting Chinese intercontinental ballistic missiles in South Korean airspace, because they would be traveling on too high a path. Perhaps the Chinese are worried that THAAD could at least track their missiles, but experts say the U.S. and Japan already can do that.

CNN reported that Defense Secretary James Mattis said China should not be worried.

“There is no other nation that needs to be concerned about THAAD other than North Korea if they’re engaged in something that’s offensive,” CNN reported Mattis as saying.

Regardless, THAAD is in Korea to stay for the time being. According to Wired, the only concern about it is that more are needed.
Besides South Korea and stateside sites, the U.S. also has deployed THAAD to Guam and the United Arab Emirates.